The present invention relates to vehicle safety devices and more particularly to a vehicle safety device of the type which uses a protector bag which is adapted to be inflated by gas under pressure in response to a collision condition encountered by the vehicle equipped with the device. The protector bag is moved, while being expanded, into a protective position intervening between a structural part of the vehicle, such as for example the windshield, the instrument panel or the steering wheel and the vehicle occupant who is flung forward during a head-on collision of the vehicle. The safety device of the described character is, thus, useful for the protection of a vehicle occupant from injury during a collision, particularly a head-on collision, encountered by the vehicle and is for this reason installed in a number of vehicles such as passenger cars. The present invention is, more specifically, concerned with a protector bag for use in such a vehicle safety device and with a method of producing the novel protector bag proposed herein.
As is well known in the art, a compact configuration, ease of manufacture and a low production cost are among the most important design considerations of an inflatable confinement, let alone the reliability of operation such as the resistance to the pressure which is to be suddenly developed in the confinement during a collision condition. Prior art protector bags are, however, so formed that they have generally spherical or spheroidal shapes when expanded under unloaded conditions and, for this reason, the above-mentioned requirements have not been satisfactorily met because of the low production efficiency that has resulted from the specific configuration of the protector bags. A typical example of the prior art protector bags is produced from a pair of flat sheet materials of, usually, a woven fabric coated with a gas-impermeable resin. Congruent circular sections are cut from these sheet materials and are seamed or bonded together along their entire circumferences. When the protector bag thus produced is expanded to its full capacity, the bag has a generally spheroidal configuration having an equatorial circumference along its seam. A number of scraps or snippets of the blanks is thus produced after the circular sections are cut from the sheet materials which usually are rectangular. The scraps or snippets must be discarded as useless and give rise to a low production efficiency and a high production cost of the protector bag and accordingly the safety device using the protector bag. The time-consuming process to seam or bond the two circular sections together provides another cause of the low production efficiency and the high production cost. The present invention contemplates elimination of all these drawbacks that have been inherent in the prior art protector bags of the vehicle safety devices of the described character.